Developer Larry Silverstein is accusing American Airlines of trying to have it both ways over whether or not the Sept. 11 terror attacks were an “act of war.”

In court papers filed this morning, Silverstein says the airline and its insurers “repeatedly and explicitly promised Congress, regulators and the American people that they would not use act of war to avoid paying claims” over the deadly hijackings by al Qaeda terrorists.

But after using those assurances to pocket “billions of dollars in taxpayer-funded benefits from a massive federal bailout,” Silverstein says American has “reversed course” and is “engaged in a shameful display of cynicism” by invoking an “‘act of war’ defense” to his negligence suit over the attack on the Twin Towers, which he leased just two months earlier.

The Manhattan federal court filing says American is “asserting with breathtaking cynicism a supposed distinction — but one without a difference — between an act of war exclusion and an act of war defense.”

“This court can and should put an end to this charade,” Silverstein lawyer Richard Williamson wrote.

Silverstein claims more than $13 billion in damages, but Judge Alvin Hellerstein has capped his potential recovery at $2.8 billion, representing the “fair market value” of his 99-year lease.

American maintains that Silverstein should’t even be able to sue because he collected more than $4 billion in insurance coverage, but Hellerstein rejected that argument last year.

American spokesman Sean Collins said: “This motion by the Silverstein interests has no factual or legal support.”

“American Airlines has defended itself with all defenses available at law against the baseless attempt by the Silverstein entities to hold American responsible for the terrorist attacks of September 11,” he added.